There exists a need for a fine particle size in order to sinter rare earth magnets. In the past, the requisite particle size has been obtained using a milling machine to obtain a relatively small particle size of about 37 microns; and then using a jet mill to obtain an even smaller size of about 3 to 10 microns. The difficulty with the foregoing method is that the oxygen and water vapor in the air cause the magnetic material to decompose.
One way of overcoming this has been to use a glove box where all steps are carried out with only minimal oxygen and water vapor present. Such a method however, is laborious and time consuming.